@InProceedings{libkin:LIPIcs.ICDT.2015.94,
  author =	{Libkin, Leonid},
  title =	{{SQL's Three-Valued Logic and Certain Answers}},
  booktitle =	{18th International Conference on Database Theory (ICDT 2015)},
  pages =	{94--109},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-79-8},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{31},
  editor =	{Arenas, Marcelo and Ugarte, Mart{\'\i}n},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2015.94},
  URN =		{urn:nbn:de:0030-drops-49791},
  doi =		{10.4230/LIPIcs.ICDT.2015.94},
  annote =	{Keywords: Null values, incomplete information, query evaluation, three-valued logic, certain answers}
}